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X-ray structural studies of lomeridine dihydrochloride polymorphs
Y Hiramatsu1, H Suzuki, A Kuchiki
1Pharmaceuticals Research Center, Kanebo, Ltd., Osaka, Japan.
Journal of Pharmaceutical Sciences
|July 1, 1996
Summary
Two polymorphs of lomeridine dihydrochloride were studied. Form I is suitable for pharmaceutical preparations due to its stable anhydrate form, unlike form II.
Area of Science:
- Solid-state chemistry
- Pharmaceutical sciences
Background:
- Lomeridine dihydrochloride is a compound with potential pharmaceutical applications.
- Understanding its solid-state properties, specifically polymorphism, is crucial for drug development.
Purpose of the Study:
- To prepare and characterize two polymorphs (forms I and II) of lomeridine dihydrochloride.
- To investigate the structural, thermal, and hygroscopic properties of each polymorph.
- To determine the suitability of each polymorph for pharmaceutical preparations.
Main Methods:
- X-ray powder diffractometry
- Infrared spectroscopy (IR)
- Thermal analysis (DTA)
- Moisture absorption equilibrium studies
- Three-dimensional X-ray analysis
Main Results:
- Both polymorphs formed hydrogen bonds between hydrochloric acid and piperazine nitrogen atoms, with distinct distances in forms I and II.
- IR and DTA profiles revealed differences attributed to hydrogen bonding and hydrochloric acid release.
- Form I exhibited a stable anhydrate form across a wide relative humidity range (0-64% RH).
- Form II showed a limited stability range (20-51% RH) for its molecular composition.
Conclusions:
- Form I of lomeridine dihydrochloride is more stable and suitable for pharmaceutical preparations compared to form II.
- The observed differences in hydrogen bonding and hygroscopicity significantly impact the pharmaceutical viability of the polymorphs.